Flyways and evolution of birds. - V.N. Grishchenko. - Berkut. 3 (2). 1994.
The forming regularities and origin of bird flyways are discussed. According to the present notions they are parts of the migration area with the higher concentration of birds and exist within the wide front of migration. The flyways of different levels were described. The net of them forms the original well-regulated structure within the migration area. It has arisen in the process of evolution after the appearance of migrations. The origin of flyways has the energy base. It is known that a dynamic system with the well regulated inside structure spends on the whole less energy. A migrating population of birds can be considered as a such system too. It is profitable for it in the evolutionary aspect to spend the minimum of energy for reaching the wintering places and breeding area. Flyway is the part of species migration area, where migration can go with the minimum expense of energy, i. e. the optimum way in these conditions. 4 main factors influence on forming of flyways: the possibility of migration generally in this place (the narrow front of migration usually forms so, it is the extreme case of forming the flyways); optimum conditions of migration in this place (aerodynamic, protective, orientation and other aspects); minimum of the distance; optimum of feeding conditions of the place. Forming of flyways is considered on examples of the White Stork arid the Crane. The rise and situation of flyways of the spring and autumn migrations in Ukraine are good explained by the action of the above-mentioned factors. [Russian].
Key words: migration, flyway, evolution, energy.